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Questions and Answers
What protozoan primarily causes malaria?
What protozoan primarily causes malaria?
Plasmodium falciparum
Which stage of the malaria life cycle involves sporozoites released into the blood?
Which stage of the malaria life cycle involves sporozoites released into the blood?
The erythrocytic schizonticides are used for the prophylaxis of acute malaria episodes.
The erythrocytic schizonticides are used for the prophylaxis of acute malaria episodes.
True
Which of the following agents is an exo-erythrocytic schizonticide?
Which of the following agents is an exo-erythrocytic schizonticide?
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Match the following antimalarial classes with their effects:
Match the following antimalarial classes with their effects:
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What is the primary aim of preventing malaria in pregnancy?
What is the primary aim of preventing malaria in pregnancy?
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Chloroquine is still commonly recommended for the treatment of uncomplicated malaria.
Chloroquine is still commonly recommended for the treatment of uncomplicated malaria.
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What is a common example of a 4-amino quinoline?
What is a common example of a 4-amino quinoline?
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Antimalarial Drug Resistance (AmDR) is the ability of a parasite to survive and multiply despite the administration of drugs at __________ doses.
Antimalarial Drug Resistance (AmDR) is the ability of a parasite to survive and multiply despite the administration of drugs at __________ doses.
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Which antimalarial therapy is recommended to prevent malaria in pregnancy?
Which antimalarial therapy is recommended to prevent malaria in pregnancy?
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Study Notes
Introduction to Malaria
- Caused by protozoan parasites, primarily Plasmodium falciparum, P. vivax, P. malariae, and P. ovale.
- P. falciparum is linked to severe morbidity and mortality, especially in sub-Saharan Africa.
Parasite Life Cycle
- Pre-erythrocytic Stage: Sporozoites enter blood via Anopheles mosquito bite, develop in the liver into schizonts, releasing merozoites.
- Exo-erythrocytic Stage: P. vivax and P. ovale form hypnozoites, dormant forms in the liver.
- Erythrocytic Stage: Merozoites invade red blood cells (RBCs), develop into schizonts, rupture to release merozoites.
Classification of Antimalarial Agents
- Classified by the life cycle stage they target and chemical structure/mechanism of action.
- Tissue Schizonticides: Target the pre-erythrocytic stage (e.g., proguanil, primaquine).
- Erythrocytic Schizonticides: Kill blood schizonts for acute malaria prevention (e.g., chloroquine, artemisinin derivatives).
- Exo-erythrocytic Schizonticides: Prevent relapse through hypnozoite elimination (e.g., primaquine).
- Gametocytocidal Agents: Destroy gametocytes, inhibiting transmission (e.g., chloroquine).
- Sporonticides: Prevent oocyte development in mosquitoes (e.g., primaquine).
Pharmacology of Selected Agents
- Quinine: An aryl amino alcohol; prevents conversion of toxic heam to hemozoin and inhibits protein synthesis. Can cause cinchonism (tinnitus, nausea).
- Chloroquine (CQ): A 4-aminoquinoline; primarily used for uncomplicated malaria. Can cause blurring of vision and skin reactions.
- Atovaquone (AQ): Another 4-aminoquinoline; used in combination therapies, associated with CNS effects like headache.
- Artemisinin Derivatives: Includes artemether and artesunate, used for acute malaria; generates free radicals destroying the parasite.
Treatment of Malaria in Pregnancy
- P. falciparum infection poses risks during pregnancy such as intrauterine fetal death and neonatal morbidity.
- WHO recommends quinine and clindamycin in the first trimester and artemisinin-based combination therapy in later trimesters for uncomplicated cases.
- Severe cases may require intravenous artesunate and transition to oral treatment when stable.
Intermittent Preventive Treatment of Malaria in Pregnancy (IPTp)
- WHO advocates for IPTp to reduce malaria episodes in pregnant women, administering sulfadoxine-pyrimethamine during antenatal visits, excluding the first trimester.
Antimalarial Drug Resistance (AmDR)
- AmDR arises when parasites survive despite effective drug dosage.
- Treatment failure can result from non-compliance, poor drug quality, monotherapy use, and absorption issues.
- Resistance primarily initiated by spontaneous mutations enhancing parasite survival under drug pressure.
Control and Prevention of AmDR
- Strategies include encouraging combination therapies, improving drug quality, and reducing transmission through vector control and personal preventive measures.
Antimalarial Combination Therapy
- Combines two or more drugs to enhance efficacy and minimize resistance emergence.
- Artemisinin-based Combination Therapy (ACT): Common regimens include combinations like AS+AQ and Art+Lume.
- Non-artemisinin-based Combinations: Include various combinations such as SP+Q and Atovaquone+Proguanil.
Conclusion
- The importance of classifying antimalarials, understanding their mechanisms, and recognizing the challenges posed by drug resistance is crucial for effective malaria management.
- Adherence to national antimalarial guidelines is vital for treating both complicated and uncomplicated malaria effectively.
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Description
Explore the essentials of antimalarial agents in this quiz, including their classification, pharmacology, and treatment considerations, particularly in pregnancy. Learn about drug resistance and combination therapies used in malaria treatment.
